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A new platinum group metal (PGM)-free proton exchange membrane fuel cell (PEMFC) cathode catalyst materials, synthesized using the VariPore™ method by Pajarito Powder, LLC, are characterized for their structure and activity. The physico-chemical analysis of the iron-nitrogen-carbon (Fe-N-C) electrocatalysts show mesoporous carbon material effectively doped with iron and nitrogen. The materials have an average pore size of 7–8 nm and high specific surface area. The Fe-N-C catalysts exhibit good oxygen reduction reaction (ORR) activity in 0.5 M H 2 SO 4 electrolyte with high half-wave potential and sustainable electrochemical stability over 10,000 repeated potential cycles with insignificant losses in their activities. As cathode catalysts in a PEMFC, the Fe-N-C materials deliver remarkably good fuel cell performance at low overpotential approaching that of the commercial Pt catalyst. The high ORR electrocatalytic activity of these Fe-N-C catalysts is credited to the synergy between nitrogen-moieties, specifically pyrrolic-N, pyridinic-N, and graphitic-N, and iron in addition to the high mesoporosity that facilitate an effective reaction path in boosting the electrocatalytic activity and stability. [Display omitted] • State-of-the-art commercial PGM-free catalysts for ORR were characterized and evaluated. • Was shown that active centres are atomically dispersed. • Performance of electrocatalysts was evaluated in industrially manufactured MEA form-factor. • The fuel cell performance is close to the state-of-the-art R&D PGM-free catalysts. [ABSTRACT FROM AUTHOR]

Ceria coated carbon nanotubes (CeO 2 @CNTs) were prepared as a versatile support material to improve both the activity and stability of platinum (Pt)-based catalysts. We demonstrated that the CeO 2 nanoparticles (NPs) had an extrinsically remote functionalization effect on the Pt electrocatalysis. The CeO 2 modulated the electronic structure, and facilitated the O 2 adsorption property of Pt without any intrinsic chemical doping or Pt-alloying. This led to d -band electron filling in Pt, and delivery of active oxygens (O−) to the Pt surface via oxygen spillover at the Pt-CeO x interface, thus enhancing the ORR activity. Furthermore, due to the unique redox behavior between Ce3+ and Ce4+, the dissolved Ce ions could also participate in the radical scavenge reaction, which prevents the chemical degradation of polymeric components in the cell. A single cell using the Pt NPs supported on CeO 2 @CNT as a cathode catalyst delivered a superior electrochemical performance and a retained durability compared to the cells with pristine CNT supported Pt NPs. • The ceria functionalized Pt/CNT (Pt@CeO 2 @CNT) was used as PEM fuel cell catalysts. • Ceria improves the ORR activity of adjacent Pt nanoparticles catalyst. • Dissolved Ce ions effectively scavenge the oxidative free radicals. • Pt@CeO 2 @CNT exhibits outstanding activity and stability in PEM fuel cells.. [ABSTRACT FROM AUTHOR]